Recently, there has been much interest in optical communications systems. Such systems find application in many areas, including telecommunications, aeronautics and remote sensing, to name a few. Optical signal modulators are typically a part of such communications systems.
Most electromechanical optical modulators are limited to data rates ranging between about 1 Mbits to 3 Mbits per second. It will be desirable, however, to attain operating speeds of about 10 Mbits per second or more for Ether Net and high-definition television (HDTV) applications. The data rate limitation arises for several reasons. One reason relates to drive voltage requirements. In most implementations, the operating speed of the modulator is approximately proportional to drive voltage, and a modulator operating at 10 Mbits per second may require a voltage in excess of 200 volts. For most modulator designs, dielectric breakdown of the modulator membrane or other parts of the modulator occurs near this voltage. During dielectric breakdown, the membrane or other structures cannot support the applied voltage. A current flows through the material, typically destroying it. In practice, it is desirable to operate at a voltage that is more than a factor of two less than the theoretical dielectric breakdown voltage, since imperfections in the materials may reduce the acceptable operating voltage. Moreover, the electronics supporting the modulator become more difficult and expensive to implement as the drive voltage increases.
As such, an electromechanical optical modulator having reduced operating voltage requirements compared with typical existing designs is needed.